1. Field of the Invention
The present invention relates to a seat adjustment device and, more particularly, to a seat adjustment device for a bike.
2. Description of the Related Art
Being disclosed in Taiwan Patent No. 258147, a bike seat adjustment device includes a C-shaped clamping seat extending from a top end of a stand pipe for a seat. An upper slide block and a retaining block are received in the clamping seat. The upper slide block is moveable relative to the retaining block. An upper notch is formed in a bottom side of the upper slide block, and an upper stop is provided on the upper notch. A clamping groove is formed in each of two sides of the retaining block. A lower notch is formed between the two clamping grooves, and a lower stop is provided on the lower notch. When the upper slide block relative to the retaining block is moved to a position where the upper stop of the upper slide block abuts against the lower stop of the retaining block, support rods for the seat can be mounted between the upper slide block and the retaining block and secured in the clamping grooves. Further, a screw is extended through the clamping seat and an arc-shaped slot of the retaining block and pressed on the retaining block, preventing the retaining block in the clamping seat from moving in an axial direction.
However, the conventional seat adjustment device has defects as follows.    1. The seat can be adjusted only at a small angle. Specifically, when the upper slide block and the retaining block pivot around in the clamping seat, they may pivot at an angle that is limited to a length of the arc-shaped slot, and thus the seat cannot be adjusted in a wide range of angle for the requirements of landforms and of folding of a bike for transportation.    2. The seat cannot be easily assembled. Specifically, when the clamping seat is loosened, the upper slide block will become loosely received in the clamping seat, so when installing the support rods in the clamping grooves, the user must simultaneously push the upper slide block for positioning, which is a troublesome assembly. Besides, during installing of the support rods, the loose upper slide block may cause noise.